High temperature capture of CO2 on Li4SiO4 sorbents via a simple dry ball-milling coupled with K2CO3 physical addition

The reversible CO 2 absorption/desorption of lithium orthosilicate (Li 4 SiO 4 ) sorbents holds potential for high temperature capture of CO 2 from hot flue gases, sorption-enhanced reforming and solar thermochemical energy storage. In this study, we have prepared a series of Li 4 SiO 4 sorbents using a combination of K 2 CO 3 addition and dry ball-milling procedure to improve the relatively slow kinetics under low CO 2 partial pressure conditions. The synergistic effects of dry ball-milling and K 2 CO 3 addition on the intrinsic properties of Li 4 SiO 4 sorbents were explored by thermogravimetric analysis and structural characterizations. Thermogravimetric analysis indicate that the highest CO 2 uptakes were achieved with dry ball-milling combined with K 2 CO 3 physical addition. The structural characterizations further reveal that this sorbent (P-3K-1.5 M) had the smallest crystallite/particle size, largest surface area, and highest availability of surface alkaline-sites. The kinetics analysis also demonstrates that P-3K-1.5 M exhibited the fastest sorption kinetics during a double process. Additionally, P-3K-1.5 M maintained a high capacity over 10 sorption/desorption cycles. Therefore, this synthesis technique, which is simple, cost-effective, and easily scalable, shows great promise for high-temperature CO 2 capture.